Cystic fibrosis mutation screening in healthy men with reduced sperm quality. A single gene mutation in the gene for Cystic Fibrosis (CF) is associated with absence of the part of the tube (the “vas deferens”) that leads from the testicle to the urethra in the penis. These men are usually carriers for the CF gene mutation and do not themselves have the disease of Cystic Fibrosis. Sperm can be recovered.
Doctors term this condition congenital bilateral absence of the vas deferens (CBAVD.) The vas deferens is a paired sperm tube that transports sperm from the testicles to the ejaculatory duct. If a man has no vas deferens, sperm is trapped in the testicle, actually the epididymis, the gland that stores sperm prior to ejaculation.